Subject: Re: Technique can pinpoint tinnitus From: Matt Flax <flatmax@xxxxxxxx> Date: Wed, 7 Oct 2009 09:10:29 +1100 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>I would like to support Arnaud's comments and expand a little... I believe it is useful to define tinnitus as either of peripheral cause or central cause - refs below. The peripheral cause is something to do with a dysfunctional cochlear amplifier (nonlinear mechancis). The central cause is to do with purely neural processes which are ill understood. When looking at brain scans of any type, it is most likely difficult to determine whether the tinnitus is of peripheral cause or central cause - unless, the scans can also see peripheral activity (activity in the inner ear and along the afferent/efferent nerves to and from the inner ear). It is clear that there are two types of tinnitus, peripheral [1] and central. The argument for a central is found when looking at the literature which discusses the success (or lack of success) when trying to treat tinnitus using surgery [2, 3, 4, 5]. Only in around 50 to 60% of cases does neurectomy solve the problem ... in these cases, one would assume that the tinnitus is peripheral - i.e. caused by peripheral cochlear amplifier dysfunction. The severing of the auditory nerve (afferents) has obvious problems - the lack of transmission to the brain, however there are also issues caused in severing the efferents. In cases when severing the efferents solves the tinnitus problem, it is most likely that the gain of the cochlear amplifier is reduced and it is taken from an unstable state to a stable state again. You can get an idea of how this would happen by referencing my compression wave cochlear amplifier model [7]. Further, tinnitus can also be induced by head injury [6]. In this case, it is possible that the inner ear is damaged and this causes a peripheral type of tinnitus, which again is a cochlear amplifier dysfunction. Until we can successfully trace this cause and develop methods such as cellular regeneration possibly using stem cells - we can tinker and experiment using all sorts of procedures to quash the problem, but they will never be as sophisticated as actually repairing the biology. [1] @xxxxxxxx{Wilson:1980a, author = {Wilson, J.P.}, title = {{Evidence for a cochlear origin for acoustic re-emissions, threshold fine-structure and tonal tinnitus}}, journal = {Hearing Research}, year = 1980, volume = 2, pages = {233--252}, number = {3-4}, month = {June} } [2] @xxxxxxxx{silverstein:1986, author = {Silverstein, H. and Haberkamp, T. and Smouha, E.}, title = {{The state of tinnitus after inner ear surgery.}}, journal = {Otolaryngol Head Neck Surg}, year = {1986}, volume = {95}, pages = {438--41}, number = {4} } [3] @xxxxxxxx{jones:1989, author = {Jones, R. and Silverstein, H. and Smouha, E.}, title = {{Long-term results of transmeatal cochleovestibular neurectomy: an analysis of 100 cases.}}, journal = {Otolaryngol Head Neck Surg}, year = {1989}, volume = {100}, pages = {22--9}, number = {1} } [4]@xxxxxxxx{wazen:1997, author = {Wazen, J.J. and Foyt, D. and Sisti, M.}, title = {{Selective cochlear neurectomy for debilitating tinnitus}}, journal = {The Annals of otology, rhinology \& laryngology}, year = {1997}, volume = {106}, pages = {568--570}, number = {7}, publisher = {Annals Publishing Compagny} } [5] @xxxxxxxx{baguley:2002, author = {Baguley, DM and Axon, P. and Winter, IM and Moffat, DA}, title = {{The effect of vestibular nerve section upon tinnitus}}, journal = {Clinical Otolaryngology and Allied Sciences}, year = {2002}, volume = {27}, pages = {219--226}, number = {4}, publisher = {Blackwell Synergy} } [6] @xxxxxxxx{ceranic:1998, author = {Ceranic, B.J. and Prasher, D.K. and Raglan, E. and Luxon, L.M.}, title = {{Tinnitus after head injury: evidence from otoacoustic emissions}}, journal = {Journal of Neurology, Neurosurgery \& Psychiatry}, year = {1998}, volume = {65}, pages = {523--529}, number = {4}, publisher = {BMJ} } [7] Introducing the Compression Wave Cochlear Amplifier M Flax, W Holmes - Conference proceedings: Interspeech 2008, 2008 On Tue, 2009-10-06 at 16:40 +0200, arnaud norena wrote: > Dear John, > > we are far from knowing the fine mechanisms of tinnitus but there is a > consensus in the field (I think) stating that tinnitus is caused by > some central mechanisms (i.e. release from central inhibition) after a > decrease in sensory inputs (caused by hearing loss). Noise trauma, > which is known to decrease spontaneous activity at cochlear nerve > level, and which is a strong and common "tinnitus inducer", > corroborate the view of a central tinnitus (a decrease in neural > activity is likely not related to a perception). Interestingly, the > percept of tinnitus corresponds strictly to the frequency range of > hearing loss (Norena et al., 2002). Moreover, it is worth mentioning > that cochlear implant subjects often present a tinnitus and that a > section of the cochlear nerve does not always abolish tinnitus. > Finally, some papers have shown neural changes (both in term of firing > rate and synchrony) after noise trauma in AI of (anesthetized) cats > circumscribed to neurons with characteristic frequency corresponding > to the frequency range of hearing loss (for instance: Norena and > Eggermont, 2003 - sorry for the self-promotion :-) ). > > This model suggests that the decrease in afferent inputs should be > compensated to prevent/reverse the central changes causing tinnitus. > Hearing aids could be a way for stimulating/reeducating the auditory > system (as long as the cochlea transmits sensory inputs, i.e. absence > of "dead regions"). However, the immediate release from tinnitus > caused by hearing aids is likely caused by the partial masking of > tinnitus by the amplified background. > > regards, > arnaud norena > > 2009/10/6 Beerends, J.G. (John) <john.beerends@xxxxxxxx> > Dear All, > > In this paper there is no mentioning of any relation between > tinnitus and hearing loss. > The spontaneous neural activity may just be the result of > unused neural capacity that was stimulated before getting > damaged. Are there any experts that know if this relation > exists? And if so, is this relation is linked to damage of > both the outer and inner hair cells, or to either one of them? > > I know experts who say that tinnitus often gets less when a > subject with hearing loss (and tinnitus) starts wearing a > correctly fitted hearing aid. This would support the idea of > hearing loss induced spontaneous neural activity. > > John Beerends > TNO > Delft > The Netherlands > > > -----Original Message----- > From: AUDITORY - Research in Auditory Perception > [mailto:AUDITORY@xxxxxxxx On Behalf Of Kevin Austin > Sent: dinsdag 6 oktober 2009 1:15 > To: AUDITORY@xxxxxxxx > Subject: Technique can pinpoint tinnitus > > > From the BBC: > > http://news.bbc.co.uk/1/hi/health/8287791.stm > > > > > Best > > Kevin > > This e-mail and its contents are subject to the DISCLAIMER at > http://www.tno.nl/disclaimer/email.html > > > > -- > Arnaud Norena > CR1 CNRS > Université de Provence > Centre St Charles, Pôle 3C - Case B > 3, Place Victor Hugo > F - 13331 Marseille Cedex 03 > +33(0)4.88.57.68.63